1. Field of the Invention
The present invention relates to an image processing technique.
2. Description of the Background Art
In general, an image pickup lens to be used for an image pickup apparatus or the like has various aberrations such as a spherical aberration and a distortion aberration. For this reason, a lens design suppressing these aberrations is performed when the image pickup lens is to be fabricated.
However, it is hard to remove these aberrations through only the lens design. For this reason, there is proposed a technique for correcting image distortion caused by an aberration of a lens through image processing on data when a subject image can be acquired as image data by means of an image pickup device.
For example, Japanese Patent Application Laid-Open No. 2011-113234 describes the technique for performing distortion correction processing on an input image such as a pickup image obtained through an image pickup lens, thereby acquiring an output image. More specifically, the Japanese Patent Application Laid-Open No. 2011-113234 describes the technique for specifying a corresponding region over an input image to a rectangular region obtained by dividing an output image and reading image data in a reference region surrounding the corresponding region, thereby executing distortion correction processing every rectangular region.
In the case in which the distortion correction processing is executed every rectangular region as in the technique described in the Japanese Patent Application Laid-Open No. 2011-113234, however, an overlapping portion is generated between respective reference regions of the adjacent rectangular regions. For this reason, a transfer quantity of image data is increased.